The present invention relates to an electromagnetic relay wherein one of the flanges of the spool is arranged inside of an opening of a case and a stationary terminal is attached to this spool. In particular, the invention relates to an electromagnetic relay wherein the problem of dust occurring at the time of the attachment of the stationary terminal is solved and the stationary terminal (in particular, a portion where a stationary contact point is provided). can be implemented so as to become attached in an excellent condition.
In general, in an electromagnetic relay a movable contact point and a stationary contact point are arranged on the side (hereinafter referred to, in some cases, as the rear side of the case) opposite to the terminal side where the edges for connection of the terminals are lead out. Then, as for the above electromagnetic relay, in many structures the movable contact point shifts in the direction of the coil axis so that the switching with respect to the stationary contact point is carried out to the conductive condition (contact condition). In such an electromagnetic relay of a conventional type, as may be seen in Japanese unexamined patent publication S56(1981)-93234 (first prior art), the stationary terminal, wherein a stationary contact point is secured on one end, is attached by a manner such as compressive insertion to a thick portion provided in a flange, located on the rear side of the case of a spool made of resin around which a coil is wound. Here, as may be seen in FIG. 2 of Japanese examined utility model publication H3(1991)-12198 (second prior art), there is also a type where the other side of the stationary terminal (edge portion for connection) is pushed into a base (substrate) which is arranged outside of the flange on the side of the terminal of the spool in a condition of penetration so as to support and fix the stationary terminal.
Here, in recent years, miniaturization and cost reduction have been increasingly required for a compact type electromagnetic relay (small type where the dimension of height is, for example, 20 mm, or less) which is mounted on a circuit substrate, or the like, in order to be mounted in a car. Therefore, further reduction of the number of portions and assembly structure of each portion in a high density have become important. Therefore, as is disclosed in Japanese unexamined patent publication H10(1998)-162712 (third prior art), a type of relay wherein one of the flanges of the spool is made to function as a base has appeared. That is to say, a member called a base which is conventionally the foundation of the assembly is eliminated and one of the flanges of the spool around which a coil of the electromagnet is wound is arranged inside of the opening of the case in the relay.
In addition, in this type of compact electromagnetic relay, which is the most widely used type,, the relay is usually sealed (that is to say, sealed type relay) in order to withstand cleaning after the mounting of the substrate or in order to secure a predetermined waterproof or dustproof condition. In particular, the cleaning of the above is carried out after soldering for the mounting of the substrate. Therefore, the relay is rapidly cooled down from the heated condition by a cleaning liquid. As a result of this, a difference in atmospheric pressure occurs between the inside and the outside of the relay so that the cleaning liquid is easily absorbed into the inside even through a slight gap and, therefore, an extreme airtightness is required.
(Technical Problem to be Solved by the Invention)
In the above conventional relay there is the problem that defects in performance are easily caused by dust which occurs due to the attachment of the stationary terminal. In addition, in the above conventional relay there is the problem that a stationary terminal (in particular, a portion where a stationary contact point is provided) cannot be implemented so as to achieve the attachment in an excellent condition.
More precisely, in the case of the first stationary terminal is secured to the flange located in the rear side of the case of the spool in the vicinity of the stationary contact point by a manner such as compressive insertion. Therefore, at the time of this securing, the resin material forming the spool is shaved by the stationary terminal, which is of metal, so that an insulating dust (shavings) occurs and this dust easily enters in between the points of contact. As a result of this, the possibility of the occurrence of the obstruction of the points of contact (fluctuation of contact resistance, defective conductance of the contact point, or the like) due to the above dust is high.
In addition, in the first prior art a structure where the flange on the rear side of the case is secured in the vicinity of the stationary contact point of the stationary terminal is provided. Therefore, the position (in particular, the position in the direction of the coil axis) of the stationary contact point changes due to deformation (warping) of the above flange in the direction of the coil axis and the contact pressure changes and, therefore, an excessive dispersion of the operational characteristics easily occurs.
That is to say, a force (i.e. pressure in the direction of the coil axis) works so that the tightly wound coil in the spool of an electromagnetic relay is led to the outside. In particular, the flange of the spool is thin in the compact (small-sized) electromagnetic relay as described previously. Thereby, a considerable amount of deformation (warping) in the form of a curved surface occurs in the flange of the spool due to the above pressure in the direction of the coil axis. As a result of this, the stationary contact point is also displaced due to the above deformation and, therefore, there is the risk that the characteristics differ greatly from the design value.
Here, a shift in the position of the contact point in the lateral direction has a comparatively small effect on the characteristics such as contact resistance and can be covered by the contact size. However, the displacement of the stationary contact point in the direction of contact (that is to say, the direction of the coil axis) along which the movable contact point shifts greatly affects the contact pressure and causes a great fluctuation in the operational characteristics and, therefore, this is, in particular, a problem.
On the other hand, in the case of the second prior reference, the place to which the stationary terminal is secured by pushing, for instance, for fitting is the base arranged outside of the flange on the terminal side of the spool which is a position far away from the stationary contact point or from the movable contact point. Therefore, the possibility of the occurrence of the obstruction of the contact point due to dust, as described above, is comparatively low. In addition, there is no problem of fluctuation in the characteristics due to deformation of the flange. However, the second prior art provides a structure wherein the entirety of a long stationary terminal is supported at only one end portion (side of the end portion for connection). Therefore, it is difficult to maintain the position of the stationary terminal as a whole in a sufficiently fixed manner (to secure the strength) and there is the problem that the positioning precision of the stationary contact point on the side of the other end is poor. Furthermore. when sufficient holding strength is to be assured by increasing supporting distance of the terminal, which has been compressively inserted within the base, then corresponding thickness of the base must become larger. Therefore, there is the disadvantage that the dimensions of the entire relay increases so as to become a larger type or the coil space decreases so that the attraction characteristics of the electromagnet become worse.
In addition, in the electromagnetic relay for mounting on a substrate as described above, of which miniaturization is strongly required, it is necessary to make the base extremely thin. Therefore, in the structure of the attachment of the stationary terminal, such as in the second prior reference described above, the positioning precision of the stationary contact point becomes particularly poor.
Furthermore, in the type where the base is eliminated as described above, the attachment to the base as in the above described first prior art is impossible and the stationary terminal must attached to the spool. Therefore, a structure of the attachment which can solve the above described problems of the first and second prior arts, that is to say, a new structure wherein the stationary terminal is attached to the spool, is required.
Thus, the present invention provides an electromagnetic relay wherein one of the flanges of the spool is arranged inside of the opening of the case and the stationary terminal is attached to this spool. In particular, a purpose of the invention is to provide an electromagnetic relay which solves the problem of dust occurring at the time of the attachment of the stationary terminal and which can implement the stationary terminal (in particular, a portion where the stationary contact point is provided) so as to achieve the attachment in an excellent condition.
(Means for Solving the Problem and Improved Working Effects in Comparison with the Prior Art)
To achieve the above purpose an electromagnetic relay according to Claim 1 is characterized in that, in an electromagnetic relay which is covered by a case of which the side of one end is open, wherein one of the flanges of the spool around which the coil of the electromagnet is wound is arranged inside of the opening of the above case and the other flange of the above spool is arranged on the rear side of the above case and which has a stationary terminal of which the stationary contact point is provided at a tip which extends towards the rear side of the above case, a protruding portion extending from the above stationary terminal is compressively inserted in a hole created in the above first flange and an engagement portion formed in the above second flange is engaged in the vicinity of the stationary contact point of the above stationary terminal and, thereby, the above stationary terminal is attached to the spool.
Accordingly, in the electromagnetic relay according to the present invention, the protruding portion extending from the stationary terminal is compressively inserted into the hole formed in one of the flanges of the spool arranged on the side of the case with the opening and the engagement portion formed in the other flange arranged on the rear side of the case is engaged to the vicinity of the stationary contact point of the stationary terminal and, thereby, the stationary terminal is attached to the spool.
Thereby, the stationary terminal is supported with the sides of both ends so that a sufficient positioning precision can be gained without making the insertion dimensions large by making the flange thick. In addition, the stationary terminal is supported through a simple engagement without being compressively inserted in the vicinity of the contact point. Therefore, the possibility of causing contact obstruction due to the invasion of shavings (dust), which occurs through compressively inserting process, between the points of contact is remarkably reduced.
In addition, an electromagnetic relay according to Claim 2 is characterized in that the above engagement portion regulates only a shift of the above stationary terminal in the lateral direction perpendicular to the direction of the coil axis and the above stationary terminal can, at least, shift in the direction of the coil axis relative to this engagement portion.
Accordingly, even in the case that the flange becomes deformed in a manner of warping into the form of a curved surface due to the above pressure in the direction of the coil axis, the flange alone is deformed so that the deformation of the above flange is avoided. Therefore, even when the above deformation occurs, the stationary terminal is not displaced. As a result of this, the displacement of the stationary contact point in the direction of the axis which has the greatest effects on the contact pressure is avoided so that the contact characteristics are significantly stabilized.
In addition, an electromagnetic relay according to Claim 3 is characterized by having a configuration wherein a plurality of pairs of a hole in the first flange and a protruding portion of the above stationary terminal being compressively inserted into this hole in different positions regarding the lateral direction of the above first flange and of the above stationary terminal are provided so that, as for some of the holes and protruding portions, the shift of the protruding portion into the compressively inserting direction is regulated under the attached condition while, as for some other holes and protruding portions, the shift of the protruding portion into the compressively inserting direction becomes possible under the attached condition and wherein the rotation of the entirety of the above stationary terminal accompanying the shift into the compressively inserting direction of the other protruding portions is regulated by the engagement portion of the above second flange and, thereby, the entirety of the above stationary terminal is positioned and the position is maintained while the torque in the direction of the above rotation added to the above stationary terminal at the time of being compressively inserted is maintained.
Accordingly, the stationary terminal is attached under the condition where the vicinity of the stationary contact point is pressed in the lateral direction to the engagement portion. Therefore, though in the above configuration the vicinity of the stationary contact point is not compressively inserted into the flange, the condition is maintained wherein the vicinity of the stationary contact point of the stationary terminal is difficult to shift even in the lateral direction. As a result, a positional shift of the stationary terminal along the lateral direction hardly occurs and the contact characteristics are attained from this view point.
In addition, an electromagnetic relay according to Claim 4 is characterized in that the entire relay is sealed by filling in a sealing material into the side with the opening of the above case and the holes, into which the above protruding portions are compressively inserted, are made to be through holes with openings on the side with the opening of the above case so that the above sealing material is made to enter gaps between these through holes and the above protruding portions.
Accordingly, in the relay according to Claim 4, holes in one of the flanges, into which the above protruding portions are compressively inserted, are created as though holes with openings on the side of the case with the opening so that the sealing material is made to enter into the gaps between these through holes and the above protruding portions. Therefore, most of the shavings occurring due to the compressive insertion of these protruding portions become solidified with the sealing material so that the shift toward the rear side of the case is blocked. As a result of this, the possibility of the occurrence of contact obstruction due to dust is further reduced. In addition, the above protruding portions, which have been compressively inserted, are secured more solidly because of the adhesive effects of the sealing material. Therefore, an appropriate compressive insertion condition is maintained with a high reliability so that the position of the stationary terminal is maintained in an appropriate condition which is even more stable.
An electromagnetic relay according to Claim 5 is characterized in that in an electromagnetic relay of which the side of one end is covered with a case with an opening wherein one of the flanges of the spool around which a coil of an electromagnet is wound is arranged inside of the opening of the above case and a lateral direction plate portion of an L shaped yoke is fit into a recess created on the end side of this first flange so that a longitudinal direction plate portion of this -L shaped yoke is arranged so as to extend from an opening created on the bottom surface of the recess of the above first flange to the side of the other flange of the above spool along the direction of the coil axis of the above spool and wherein a movable contact point spring is secured to outer surface of the longitudinal direction plate portion of the above yoke so that the side of one end of this movable contact point spring extends from the opening of the above case in a protruding condition so as to form an edge portion for connection of the movable contact terminal and which is sealed by filling in a sealing material in the inside of the opening of the above case, a notch facing the above recess and the opening is created on the surface of the side where the above longitudinal direction plate portion is arranged in the above first flange and this notch arranges the side of one end of the above movable contact point spring into the condition of penetration through a window surrounded by the above case and the yoke and the above sealing material is filled in within the above window.
Accordingly,. the electromagnetic relay according to Claim 5 forms a notch facing the recess and the opening into which the yoke is fit on the side of the first flange of the spool. Then, a configuration is provided wherein this notch arranges the side of one end of the movable contact point spring (end portion for connection of the movable contact terminal) into the condition of penetration through a window surrounded by the case and the yoke and the sealing material is filled in within this window.
That is to say, in the present invention a lead portion of the end portion for connection of the movable contact terminal is formed so that this lead portion is sealed. Therefore, it is not necessary to add a portion in a specific form to the spool in order to prevent unnecessary invasion of the sealing material and the height dimension of the entire relay does not become large.
In addition, the operation of penetrating the side of one end of the movable contact point spring into a narrow gap at the time of assembly of the movable contact point spring, and therefore the assembly operation, becomes significantly easier even in the case that the assembly operation is done manually.
In addition, according to the present invention the above movable contact point spring is transferred in a linear manner in the direction of travel from the side of the above spool in the condition, where the above yoke is attached, to the outer surface of the above notch and the above longitudinal direction plate portion, which is in the lateral direction perpendicular to the coil axis direction. Then, the side of one end of the above movable contact point spring is fit into the above notch while the above movable contact point spring is secured to the outer surface of the longitudinal direction plate portion of the above yoke and, thereby, the above movable contact point spring can be attached. Therefore, the assembly of the movable contact point spring before the attachment of the case becomes possible by transferring the movable contact point spring in the lateral direction in a linear manner and, thereby, assembly becomes easy. As a result of this, automatic assembly becomes possible and the effects are gained that high productivity (low production cost) can be implemented.